SLOW INITIATION BY TERT-BUTOXYBENZENES IN LIVING CATIONIC POLYMERIZATION OF ISOBUTYLENE

tert-Butoxybenzenes including the 4-substituted derivatives of anisole , toluene and p-chlorobenzene have been synthesized and studied as ini tiators in combination with TiCl4 for polymerization of isobutylene (I B) in CH2Cl2/methylcyclohexane (MeCHx) solvent mixtures at -78 degrees C, Living polymerizations with slow initiation were observed by the a ll-monomer-in (AMI) and incremental monomer addition (IMA) techniques, and polymers with narrow molecular weight distribution (MWD) (M(W)/M( n) < 1.1) were obtained under certain conditions, Aging of the initiat ing system prior to charging the monomer does not improve the initiati ng efficiency, It has been found that the initiating efficiency can be increased by increasing the solvent polarity, however, the relative v olume of CH2Cl2 is limited in order to avoid polymer precipitation and bimodal MWD.